In production systems that produce products through multiple steps, there are devices that support estimation of the cause of an abnormality that has occurred. Such devices visualize the transition of steps by displaying the relationship between steps related to the amount of variation that varies in each step, where the steps are indicated on the horizontal axis.
Patent Document 1: Japanese Laid-open Patent Publication No. 2009-116842
However, with the related technology described above, there is a problem in that it is not possible to detect an abnormality related to the production system in real time. For example, with the related technology described above, for the amount of variation that varies in each step, because the relationship between the steps is displayed after all of the steps have been ended, if an abnormality occurs in each of the steps, it is not possible to detect the abnormality in real time.